If x and y are positive, is 3x > 7y?
(1) x > y + 4
(2) -5x < -14y
My ans : B OA: D
my explanation. by statement 1 let y=5, x = 10
then 3x = 30,
7y = 35
therefore : 3x<7y
now let y = 20, x = 100 then 3x = 300
and 7y = 140
therefore 3x>7y
hence not sufficient.
by statement 1 it clearly shows that 3x>7y
so IMO B
x and y
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You are right, the OA is wrong
Just remember, whenever comparing ratios to see which one is greater, if an equation includes adding or subtracting a constant, it is generally insufficient, unless the question has some type of stipulation that makes it possible.
Just remember, whenever comparing ratios to see which one is greater, if an equation includes adding or subtracting a constant, it is generally insufficient, unless the question has some type of stipulation that makes it possible.
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IMO D.
B is sufficint as you have done it
A. x>y+4
plugin values -
x= 4, y+4=3; y=-1
therefore, 3x>7y
x=-3, y+4=-4; y=-8
3x>7y
x=0, y+4=-1; y=-1
3x>7y
x=1/2, y+4=1/3; y=-11/12
3x>7y
x=-1/3; y+4=-1/2; y=-9/2
3x>7y
Hence SUFF
Ans D.
Ketkoag,
I saw your solution and it seems correct as well. I am really confused with this question.
What is the source of the question?
B is sufficint as you have done it
A. x>y+4
plugin values -
x= 4, y+4=3; y=-1
therefore, 3x>7y
x=-3, y+4=-4; y=-8
3x>7y
x=0, y+4=-1; y=-1
3x>7y
x=1/2, y+4=1/3; y=-11/12
3x>7y
x=-1/3; y+4=-1/2; y=-9/2
3x>7y
Hence SUFF
Ans D.
Ketkoag,
I saw your solution and it seems correct as well. I am really confused with this question.
What is the source of the question?
-
- Junior | Next Rank: 30 Posts
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- Joined: Fri Mar 27, 2009 4:11 am
IMO B as well as
-5x < -14y ,multiplying it by -1 and reversing the sign,
5x > 14y .....multiplying it by 3
15x > 42y
we need to find if 3x>7y ,multiplying it by 5
15x > 35y
clearly b is suff.
On stmt a,taking the discussion a bit further from schumi's solution,
if x=100 , y could be 95
clearly,3x100=300 is not greater than 95X7=665
but if x=5, y could be 1
subsituting values for x & y 15 > 7 hence stmt is insufficient
Maybe we need an expert's opinion.what you think guys?
-5x < -14y ,multiplying it by -1 and reversing the sign,
5x > 14y .....multiplying it by 3
15x > 42y
we need to find if 3x>7y ,multiplying it by 5
15x > 35y
clearly b is suff.
On stmt a,taking the discussion a bit further from schumi's solution,
if x=100 , y could be 95
clearly,3x100=300 is not greater than 95X7=665
but if x=5, y could be 1
subsituting values for x & y 15 > 7 hence stmt is insufficient
Maybe we need an expert's opinion.what you think guys?
x and y are positive..schumi_gmat wrote:IMO D.
B is sufficint as you have done it
A. x>y+4
plugin values -
x= 4, y+4=3; y=-1
therefore, 3x>7y
x=-3, y+4=-4; y=-8
3x>7y
x=0, y+4=-1; y=-1
3x>7y
x=1/2, y+4=1/3; y=-11/12
3x>7y
x=-1/3; y+4=-1/2; y=-9/2
3x>7y
Hence SUFF
Ans D.
Ketkoag,
I saw your solution and it seems correct as well. I am really confused with this question.
What is the source of the question?